Japanese mahjong scoring rules: Difference between revisions

[[Japanese mahjong]] features a very complex scoring system. Nearly every mahjong hand has a value in terms of '''han''' and '''fu''', the two scoring factors. The han and fu are plugged into an [[#Calculating basic points|equation]] to derive the value of the hand. Certain [[yaku]] are instead given a value of [[yakuman]] (or sometimes [[multiple yakuman|double yakuman]]), the highest scoring hands.

Under usual rules, above 4 han, the score is capped. Fu become irrelevant and the hand is scored based solely on the han value. Since there are not a large number of possible hand values below 5 han, a [[scoring table]] is usually used, rather than calculating the values directly.

 

By default, most games start players at 25,000 points, with the goal of scoring at least 30,000 to declare victory for the points leader. Both of these values are easily varied, and tournament play in particular often starts with 30,000 points.

 

Under the rarely-used [[aotenjou]] rules, there is no scoring cap, and every hand is evaluated for fu and han, regardless of value. This can result in absurdly high hand values.

'''Han''' {{kana|飜}} is the main portion of scoring, as each [[yaku]] is assigned a value in terms of han.  Most of the yaku are valued at either 1 or 2, but the values, not counting yakuman hands, go as high as 6 han for a closed [[chinitsu]]. Some yaku are worth [[Kuisagari|one fewer han when open]], and some cannot be scored with an open hand, but many yaku are not scored the same regardless of whether the hand is open or closed.

A hand's han value is calculated by summing together the han values of its yaku, plus the han for each [[dora]] tile in the hand. Dora are ordinarily worth 1 han each, but a tile that is dora multiple times is worth correspondingly more han.

In addition [[List of yaku|to knowing the yaku]], players are encouraged to know their han values.  This gives them greater awareness on potential point values of the hand. This knowledge may help aiding in various game decisions, particularly when [[Riichi strategy|calling riichi]] or [[Betaori|abandoning the hand]].

'''Fu''' {{kana|符}} (''pronounced as foo'') takes the hand composition into consideration in terms of [[mentsu|tile melds]], [[machi|wait patterns]] and/or win method. Every hand begins with a default start value of 20 fu. To determine the final number of fu, the sources of fu are added up along with the base number and then rounded up to the next multiple of 10. The exception is the [[chiitoitsu]] yaku, which is fixed to 25 fu and is not rounded. While fu may be counted for hands worth 5 han or greater, it is not necessary.  At 5 han and above, the hand value is dependent only on the han count, and the fu count is ignored. When playing with the uncommon [[aotenjou]] rule, however, the fu count is used for hands of any han value.

The highest-scoring combinations are the yakuman patterns. A hand completing a yakuman is not normally scored for han and fu, but depending on the rules, it may be possible to combine multiple yakuman for an even larger hand.

 

Under [[aotenjou]] rules, where there is no scoring limit, a yakuman is scored as a 13-han yaku, and a double yakuman as a 26-han yaku.

# If the hand is a [[List of yaku|yakuman]], then hand scores 8,000 basic points.

## If double yakuman are used, a double yakuman scores 16,000 points.

## If multiple yakuman are used, and multiple single and/or double yakuman are completed, their values are added together.

# Otherwise, determine the hand's valid [[yaku]]. Be sure not to count [[Yaku compatibility|invalid combinations]] such as [[chanta]] + [[junchan]].

# Count any number of dora to the han count.

# If the han count is 5 or more, then counting fu is no longer necessary. Score the hand according to its han value:

# To get the base points, multiply the fu value by four, and then double it for each han ('''fu × 2^{(2 + han)}''').

At the end of the game, the raw points are used to calculate the end game score. These are the two or three digit +/- numbers used to reflect a player's score. Instead of 30,000 points, a player's score may actually be displayed as +40.0. <!-- To this day, I don't know why this system exists-->

* [http://jbcs.info/Mahjong/hand/calculator.html Online hand scoring calculator]